Concave spiral separator



J1. 311, 939 F. PARDEE CONCAVE SPIRAL SEPARATOR Filed March 30, 1937 2Sheets-Sheet l INVENTOR;

BY fir- 4 MACE] RDEE.

ATTORNEYS Emma 33b1, 1m PAR'DEE 5 3 'CONCAVE SPIRAL SEPARATOR FiledMarch 50, 1957 2 Sheeis-$he ai 2 ATTORAIEYE Patented Jan. 31, 1939UNITED STATES PATENT OFFICE CONCAVE- SPIRAL SEPARATOR Application March30, 1937, Serial No. 133,776

8 Claims.

This invention relates to separators of the spiral or helical type, inwhich materials of varying specific gravities and frictionalcharacteristics are separated into different streams as they flow alongthe runway.

In separators of this type, previously invented and patented by me, therunways have frequently progressed along a spiral or helical path, suchrunways being inclined downwardly and inwardly toward the ax s of theseparator in a straight transverse line.

While such separators have been successfully used for many years, it isnevertheless a fact that in separating coal and slate, the slate beingthe heavier material, has a. tendency to first move inwardly toward thecentral axis and then, because of the steeper drop near the axis, togain momentum and thus move crosswise or outwardly and into the path onthe spiral runway where only coal is supposed to travel. Thus thematerials in the old spiral separators do not travel downwardly in atruly constant spiral line. That is to say, the path of travel as viewedin plan, does not correspond to a circle centered on the axis of theseparator.

The present invention is based upon my recent discovery that, if therunway surface of the separator instead of being inclined radiallyinward along a straight line as heretofore, is transversely curved, thusforming a helical valley, a decided improvement in the separation can beeffected and for any given lump size of material handled, apredetermined zone or region of separation can be maintained along asubstantially constant spiral line. Thus the material to be separatedwill follow a substantially constant helical path which, in plan View,will correspond substantially to a true circle.

One of the chief features of the present inven- 0 tion is the provisionof a helical or spiral separator having such a transversely concavedrunway. The location of the valley line or zone of separation, asmeasured transversely of the runway, will vary for different lump sizesof material, although the helical pitch or drop for a given turn aroundthe helix or spiral may remain constant. For example, the helical lineof travel for small size lumps of material on a runway of givenlongitudinal or helical pitch will be along 50 the line of a circle of arelatively small diameter, as viewed in plan, while the line ofseparation for larger lmnps will be along the line of a circle of largerdiameter viewed in plan. A more detailed feature of the inventioncontemplates pro- 55 vision of guide means at the delivery end of theseparator for guiding material coming from one side of the line ofseparation toward one discharge point and guiding material coming fromthe other side of separation to another discharge point.

This guide means will preferably be laterally 5' adjustable so that fora given separator it can be varied to suit slight changes in the zone ofseparation when handling materials of slightly differing lump sizes. Theabove and other more detailed features of the invention will be fully 10apparent from the following detailed disclosure when read in connectionwith the accompanying drawings.

In the drawings- Fig. l is a somewhat diagrammatic elevation-l5illustrating the contour lines of one embodiment of the invention; Fig.2 is a side elevation illustrating one turn of the separator runway;Fig. 3 is a plan view thereof; Fig. 4 is a fragmentary plan view showingone of the plate-like sections 20 of the separator runway and a portionof the central supporting column; Fig. 5 is a section takenapproximately on line 5-5 of Fig. 4; Fig. 6 is a similar sectionillustrating a modified construction; Fig. 7 is a plan view of one ofthe'run- 25 way plates in flat condition before being warped or formedto produce the concave runway surface; Fig. 8 is a fragmentary plan Viewof the delivery end of the separator showing adjustable guide means fordirecting differing materials to 30 separate storage points; Fig. 9 isan end elevation thereof, and Fig. 10 is an enlarged detail of theadjustable guide means.

Referring in detail to the drawings, i0 represents a central supportingpost, to which may 35 be secured suitable supporting rods or bracketsII, on which will rest a plurality of plate-like sections l2, which areoverlapped and riveted as at l3 or otherwise secured to one another, soas to form a substantially continuous helical runway.

Heretofore, the runways of spiral separators have been so disposed thatthe runway surface, as viewed from any substantially radial verticalplane, will be inclined in a straight line downwardly and inwardly at anangle, for example, as indicated by the broken lines (1-!) in Figs. 1and 5. This straight line radial inclination of the runway toward theaxis of the helix is now generally known in the art as the flare.

Such a straight flare on the runway surface results in a very rapid dropof the material particularly in the zone nearest the axis thereof.According to the present invention, instead of having a straight inwardflare, I provide what may be termed a transversely concaved flare, suchas shown on an enlarged scale in Fig. 5. Such concavity of the runway atvarious points throughout the length of the runway is indicatedgraphically in the diagrammatic view of Fig. 1. In this figure, thestraight broken lines a-b correspond to the old form of straight flarerunway surface. The line a.b at the top of Fig. 1 may be considered aslying along a horizontal center line of Fig. 3 passing through the axisof the post l0.

' In the novel separator of the present invention I provide a runwayhaving a concave supporting surface, such as illustrated, forming avalley between the inner and outer edges of the runway. For a given lumpsize of material handled, there will be a substantially constant helicalzone or line of separation, such as indicated by the dotted line -0 inFigs. 4 and 5, or by the dotted circle 0 in Fig. 3. These lines crepresent the lowest point in the valley of the runway. The location ofthis valley or zone of separation will vary for different sizes ofmaterial. For example, for separating materials of the relatively largelump size known as egg, the zone of separation may be considered astaking place along the line cc--c. Assuming that a larger lump size isto be handled, the low point in the valley or zone of. separation willlie at a greater distance from the vertical axis of the separator, forexample, along the helical line indicated at 11-11. In the improvedseparator, therefore, the runway surface is depressed between its innerand outer edges, thus forming the concave surface acd/b of Fig. 5. Thiscross-sectional configuration provides what I term a valley whichcorresponds to the zone or line of separation.

, This valley or helical zone of separation will be located at differentpredetermined radial distances, depending upon the lump size of materialbeing handled. That is to say, that for a separator adapted to handlesmall size lump mavterial, the valley will be located nearer the centeror axis of the separator than will be the case for i a separator adaptedto handle large size lump material.

In operation when the separator is used for ridding coal of slateinitially mixed therewith, the slate or heavier material traveling alongthe runway will slide or move inwardly toward the axis, and the coal orlighter material will work its way outwardly and eventually travel in apath along the outer side of. the line or zone of separation. Thisuniformity of helical travel is a novel functional characteristic whichcould not be attained by my old types of separators which had a straightline inward flare.

The difference between the action of my old separators and the novel oneof the present invention will be apparent from reference to Fig. 5, whentaken with the following explanation.

The inner part of the concave surface of the improved runway provides anupward inclination on one side of the line cc, while in the old form ofstraight flare the runway surface from the inside of the said line ccwas inclined downwardly toward the axis of the separator. Theinclination of the surface of the runway outwardly from the line ofseparation 0-0 in the case of the novel concaved runway is relativelysteeper than the old straight flare runway, as will be apparent bycomparison of the curved portion c-db of Fig. 5 with the straight lineportion a'b corresponding to the old straight inward flare.

fact that the runway was inclined toward the axis caused the largerparticles of slate to gain momentum and cut crosswise and enter theouter coal stream instead of continuing downward in a true helical path.This difficulty is overcome by the present invention by the relativelysimple yet heretofore unobvious expedient of forming the runway with aconcaved flare above de scribed.

Tests, which I have made show that with such a concave flare theobjectional cross-flow of slate is overcome and thus the separation onmy new separator takes place along a substantially constant helical pathfor any given lump size.

With the improved runway having the concaved flare, the upwardly curvedor inclined surface on the inner part of the separator runway willresult in a slowing up of the slate travel. At the same time, it willslightly retard the coal travel. The net result of this, combined withthe action of gravity, friction and centrifugal forcewill, for a givenhelical pitch, give the materials a greater time interval to bring aboutthe desired separation into different streams, as they travel helicallydownward along the runway surface. Thus, it is clear that, as comparedwith the old type of straight line flare, the novel concave flare of thepresent invention results in an important functional improvement.

The concave runway is produced by taking relatively flat plates, such asshown in Fig. '7, and bending or warping them to the desired concavecurvature. However, in some cases, instead of having a curved concaveconfiguration the concavity may be in the nature of oppositely inclinedstraight surfaces. 7 Such a modification is shown in detail in Fig. 6.

While the concave runway referred to will usually be formed of aplurality of bent plate-like sections, with the lower edges of one plateoverlapping the upper edge of the next lower plate, the plates may bearranged with their adjacent edges abutting and united by flush seamwelds. Or, the sections may be formed of cast metal of the concave formdescribed.

At the lower discharge end of the separator, I preferably provideadjustable guide means adapted to direct the inner flowing stream of.slate to one storage point and the outer flowing stream of coal toanother point. This guide means is preferably mounted in such a manneras to permit of lateral adjustment to suit slightly different lump sizesto be handled on a given concaved runway.

By way of illustration, I have shown such an adjustable mounting inFigs. 8 to 10, wherein there is a block 14 having slots l5 thereinthrough which pass fastening bolts [6, which extend through the plate tothe lowermost section of the runway. It will be understood that, byloosening the nuts I! on the bolts, the block M can be adjustedlaterally so as to position this guide device as a whole to suitdifferent lump sizes of material handled. The guide element of thisdevice in the embodiment illustrated is in the form of a rod I8extending substantially tangent to the line of separation, for example,the line c--c. To permit of still finer adjustment, the rod It may bemounted eccentrically on an elongated bolt l9. Thus, a rough lateraladjustand a finer or more precise adjustment may be secured by turningthe rod l8 about its eccentric bolt mounting l9. Below the guide rod I8,I provide a partition 20 serving as a separating barrier to preventintermixture of, the coal and slate, as it drops into the chute 2! to beled to suitable storage receptacles, not shown. The chute 2i may beconveniently secured at its end to the block M, as shown.

While I have described quite precisely certain specific embodiments oftheinvention illustrated it is to be understood that variousmodifications and substitution of equivalents may be made by thoseskilled in the art without departure from the invention as defined inthe appended claims.

What I claim is:

1. A separator of the character described comprising a stationaryhelical runway of fixed vertical pitch suflicient to cause material toslide thereon by gravity and having a supporting surface depresseddownwardly from its inner edge for a substantial distance therefrom andthence upwardly to an outer edge above the level of the inner edge toform a helical valley of concave upward flare effective to separatematerials of a given lump size but of different specific gravities andfrictional characteristics along a helical zone or line of predeterminedpitch and diameter.

2. A separator of the character described comprising a stationaryhelical runway of fixed vertical pitch sufficient to cause material toslide thereon by gravity and having a supporting surface depresseddownwardly from its inner edge for a substantial distance therefrom andthence upwardly to an outer edge above the level of the inner edge toform a helical valley of concave upward flare effective to separatematerials of a given lump size but of different specific gravities andfrictional characteristics along a helical zone or line of predeterminedpitch and diameter and laterally adjustable guide means for directingthe separated materials to different discharge points.

3. A separator of the character described comprising a stationaryhelical runway of fixed vertical pitch sufficient to cause material toslide thereon by gravity and having a supporting surface depresseddownwardly from its inner edge for a substantial distance therefrom andthence upwardly to an outer edge above the level of the inner edge toform a helical valley of concave upward flare effective to separatematerials of a given lump size but of different specific gravities andfrictional pitch and diameter, laterally adjustable guide means fordirecting the separated materials to different discharge points andmeans adjustably secured at the lower end of the separator runway fordirecting the separated materials to different discharge points.

4. A separator of the character described comprising a stationaryvertical post, a' stationary helical runway of fixed vertical pitchsufficient to cause material to slide thereonby gravity, secured at itsinner edge to said post and having a separating surface depresseddownwardly from its inner edge for a substantial distance therefrom andthence upwardly to an outer edge above the level of the inner edge toform a helical valley of concave upward flare effective to separatematerials of a given lump size but of different specific gravities andfrictional characteristics along a helical zone or line of predeterminedpitch and diameter.

5. A separator of the character described comprising a stationaryhelical runway of fixed vertical pitch suflicient to cause material toslide thereon by gravity and having a supporting surface depresseddownwardly from its inner edge for a substantial distance therefrom andthence upwardly to an outer edge above the level of the inner edge toform a helical valley of concave ties and frictional characteristicsalong a helical zone or line of predetermined pitch and diameter, thelowermost point in said valley being nearer the inner edge than theouter edge.

6. The separator of claim 1 in which said separating surface is concavedin a radial direction on a smooth unbroken curve.

7. The separator of claim 1 in which said separating surface isdepressed to an angle extending helically at a distance from the inneredge of said surface and then extends upwardly to the outward edge edgethereof.

8. The separator of claim 1 in which said separating surface is made ofa succession of plates having the lower edge of one plate overlappingthe upper edge of a successive plate.

FRANK PARDEE.

